High speed printer hammer assembly



1966 c. l. WASSEERMANN 3,289,575

HIGH SPEED PRINTER HAMMER ASSEMBLY I5 Sheets-Sheet 1 Filed Jan. 8, 1964FIG I INVENTOR.

CARLI-WASSERMANN Q MMM ATTORNEY 5 c. l. WASSERMANN 3,

HIGH SPEED PRINTER HAMMER ASSEMBLY 5 Sheets-Sheet 3 Filed Jan. 8, 1964FIG.6

FIG.

INVENTOR.

CARLI. WASSERMANN ATTORNEY Dec. 1966 c. l. WASSERMANN 3,

HIGH SPEED PRINTER HAMMER ASSEMBLY Filed Jan. 8, 1964 5 Sheets-Sheet 5 IN V ENTOR.

CARLLWASSERMANN BY w Wwm ATTORNEY United States Patent Ofiice 3,289,575HIGH SPEED PRINTER HAMMER ASSEMBLY Carl I. Wassermann, Queens Village,N.Y., assignor to Datamark, Inc., Westbury, N.Y., a corporation of NewYork Filed Jan. 8, 1964, Ser. No. 336,519 Claims. (Cl. 101-93) Thepresent invention concerns high speed printers and, in particular, novelprinting hammer means for such printers.

The present invention is particularly concerned with, although notlimited to, that type of printing device having a continuously rotatingtypewheel cooperating with a plurality of electromagnetically operatedprinting hammers. The paper is fed between the typewheel and thehammers, and at appropriate times the several hammers are independentlyactuated to print the different characters involved. This arrangement isnow well known in the art as a means for printing the output ofelectronic computers and the like. While such printers are widely used,many problems remain to be solved. In addition, many operatingcharacteristics of such printers are badly in need of improvement.Furthermore, more exacting requirements are being introduced almostdaily as, for example, requirements for greater speed of operation andfor greater reliability. The operation of the printing hammers is basicto these problems and the state-of-theart is constantly being pushed inthis area.

Some of the problems associated with printing hammer design includemechanical alignment, speed of response, uniformity of impact forces andflight time, transient response, power sensitivity, temperaturesensitivity, interaction between driving coils, operating life, andspacing. In accordance with the present invention significatimprovements have been made in all of these design areas. According tothe present invention the hammer actuators are flat stampings readilyand precisely made, which are mounted by means of leaf springs doingaway with alignment problems associated with pivots and other types ofbearings. The spring mounting has been found to improve the transientresponse of the hammers and to greatly prolong their useful life.Adjustable hammer damping and rebound adjusting means as well as forsetting the initial magnet air-gap are provided. The stackingarrangement providing six hammers to a module permits greater spacingbetween physically adjacent drive coils. It has been found that whenthis spacing is increased the coupling between coils decreases at a veryrapid rate. The greater spacing also permits omitting shielding whichhas been found to greatly increase the power sensitivity of the hammerdrive, an important advantage.

Accordingly, one object of the present invention is to provide methodsof and means for greatly improving and simplifying the construction andoperation of high speed printing hammers and printing hammer assemblies.

Another object is to simplify the alignment procedures required foraccurate operation of high speed printing hammers.

Still another object is to provide faster operating and longer life highspeed printing hammers and high speed printing hammer assemblies.

A further object is to provide printing hammers which operate withimproved transient characteristics.

A still further object is to provide printing hammers and printinghammer assemblies in which interaction 3,289,575 Patented Dec. 6, 1966and shielding problems are minimized and power sensitivity is increased.

These and other objects of the present invention will be apparent fromthe detailed description of the invention given in connection with thevarious figures of the drawing.

In the drawing:

FIGURE 1 is a view of atom hammer module in accordance with the presentinvention with mounting means omitted to permit a clear showing of thearrangement of parts.

FIGURE 2 is a view of the crossed springs used to mount three hammeractuating arms.

FIGURES 3 and 4 are plan views of the two fiat springs used in theassembly shown in FIG. 2.

FIGURE 5 is a perspective view of three hammers with their supportingsprings in accordance with the present invention.

FIGURE 6 is a perspective view of a magnet and coil assembly suitablefor use in the device in. accordance with the present invention. I

FIGURE 7 is a perspective view of a supporting member for three hammeractuators showing one hammer actuator in place in accordance with thepresent invention.

FIGURE 8 is a perspective view of a frame suitable 'for mounting sixhammer actuators and their magnets showing one three actuator mountingmember and one hammer actuator in place. 7

FIG. 1 shows the relative arrangement of hammers and actuators making upa six hammer module: to print in conjunction with a type drum 1 shown indot-dash partial outline. The six hammers are spring suspended, threehanging down from mounting block 2 and three standing up from mountingblock 3. For example, hammer 4 which is a rod-like piece of metal issupported from mounting block 3 by means of springs 5, 6 and 6' whilehammer 27 is hung from mounting block .2 by means of springs 28 and 28'and a third spring corresponding to spring 6 for the other hammer butwhich cannot be readily seen. The mounting blocks 2 and 3 are made up ofmain portions with one removable portion at one end as 30 for clampingone row of springs and two removable portions at the other end as 29 and30 for clamping two rows of springs. When one end of any of thesehammers is tapped at its end which is remote from the type drum, itmoves in free flight to press a printing medium, not shown, against apredetermined type face on the type drum. The spring suspension of thehammers allows them tomove freely with essentially no friction todeliver the kinetic energy imported at one end to the printing point atthe type drum surface.

The hammer actuators are flat metal arms as, for example, arm 7 havingan enlarged end 8 for striking its corresponding hammer and an enlargedend 9 for receiving efficient attractive force from its driving magnetconsisting of core 12, coils 10 and a mounting bracket 11. The actuatorarm 7 is suspended by means of crossed fiat springs 13 and 14 mounted ona mounting device shown in FIG. 7. When magnet core is magnetized bypassing current through coil 10, the enlarged end 9 of arm 7 is pulledtoward the core 12 and arm 7 pivoting around supporting springs 13 and14 enlarged end 8 moves into contact with the outer end of hammer 4imparting to it a flying motion toward the type drum 1 where it pressesthe printing medium, not shown, against a predetermined type face, notshown, carried on the surface of the drum.

It can be seen that the crossed flat springs 13 and 14 provide a stiffand inflexible mounting in two mutually perpendicular directions whileallowing spring biased but otherwise free and substantially frictionlessmotion in a third direction perpendicular to the two directions ofstiffness. In a similar manner springs 13 and 14 support thetwoadditional arms 16 and 18 to be actuated by magnets 26 and 25respectively and adapted to strike two additional hammers of the groupof six illustrated. Three more actuating arms 15, 17 and 19 are showninterleaved with the three just described and supported by crossedsprings 21 and 22. These arms are actuated by magnets 20, 24 and 23respectively and serve to strike the remaining hammers of the six shown.The supporting method and means for the actuator arms is shown in FIGS.7 and 8.

FIG. 2 is a perspective view of the crossed spring assembly consistingof springs 13 and 14 showing how they are cut-out and notched to permitthe crossed arrangement.

FIG. 3 shows a plan view of spring 13 illustrating how it is cut-out tointerleave with spring 14 and notched to permit assembly with spring 14as shown in FIG. 2.

FIG. 4 similarly shows a plan view of spring 14 illustrating how it iscut-out to interleave with spring 13 and notched to permit assembly withspring 13 as shown in FIG. 2. The cut-out portions and notching ofsprings 13 and 14 not only provide means for easy assembly but thesecut-outs and notches provide a simple means for controlling thestiffness of these springs. The mounting holes adapted to permit screwfastening to the spring mountings also permit a slight adjustment of thehammer actuator position in two dimensions for accurate alignmentpurposes.

FIG. shows a group of three hammers. These three interleaved with threemore similar hammers go to make up the total of six hammers in onemodule assembly. (FIG. 1 shows the six hammer assembly withcorresponding numbering.) These three hammers as illustrated by hammer 4are held in rigid parallel relationship by suspension springs 5, 6 and6. The spring mounting provides rigidity in two directions whilepermitting substantially frictionless motion in one direction which isthe direction along the axis of the hammer. The ends of the hammers maybe enlarged somewhat to provide enlarged striking areas at each end.

FIG. 6 shows a perspective view of a typical electromagnet used toimpart motion to the hammer actuators. This electromagnet is a simpleframe 11 holding two coils embracing two iron cores 12.

FIG. 7 is a perspective view of hammer actuator mounting member whichprovides a seat for the crossed springs 13 and 14. This mounting memberwill generally consist of a casting 31 including a lug 32, mounting andlocating holes 33, 34 and 44, and mutually perpendicular seating areas37 and 37 where springs 13 and 14 may be secured as by screws 43 and 42respectively. A mounting block 39 is provided for attaching arm 35 tosprings 13 and 14. One hammer actuator 35-41 is shown mounted on springs13 and 14. This actuator includes hammer impulse enlarged end 40 andmagnet armature end 36.

FIG. 8 is a perspective view of a module frame 45 suitable for mountingthe six hammer actuator and magnet means show in FIG. 1 by means of twoactuator mounting members one of which is shown in place at 31. Thisview shows how actuator mounting member 31 is located on studs 45, 46and 52, one actuator 41 is shown and one magnet 47. A second actuatormounting member to accommodate three more actuators mounts in aninverted position with respect to 31 on studs 53, 54 and 56. Certainother studs and surfaces to permit accurately mounting and locatingmodule frame 45 are shown at 48, 49, 50, 51 and 57. The hammeractuators, as illustratcd by actuator 41, include a projecting arm 58adapted to be positioned by an adjustment screw 59 turning in a threadedhole 60 in frame 45 the purpose of which is to provide means foradjusting the initial air-gap between the enlarged magnet end of the armand the magnet (see 9 and 10 in FIG. 1). Damping means are also providedfor the hammer springs as the damping pad 64 carried on spring 63,adjustable by means of screw 62 carried by frame part 61 which may beattached to casting 31 in any convenient manner and adapted to contactand damp one or more of the hammer springs (as 5, 6 or 6' in FIG. 1) ata predetermined point in the hammer flight.

It can be seen from FIGS. 1 and 8 that the six element module providessix actuators, hammers and magnets in a relatively thin assembly and atthe same time it locates the magnets in widely spaced positions. Also itcan be seen that if another similar module is stacked adjacent to theone illustrated that the magnets of the adjacent modules will belaterally spaced center to center by an amount equal to the modulethickness plus any space left between modules, in this case a pitchequal to six characters on the drum. It has been found that due to thisphysical spacing that there is no serious interference between magnetseven without shielding of the individual magnets. This not only makesthe system easier and cheaper to construct but it reduces the powerrequired to actuate the hammers by a substantial amount. It should bepointed out that the thickness of a six element module must besubstantially equal to the total linear displacement of six type faceson the type drum.

From the above description and the various figures of the drawing itwill be seen that the present invention provides a high speed printerhammer arrangement having a number of unique characteristics andadvantages. The hammers being mounted by means of fiat springs extendingperpendicular to the rod-like bodies of the hammers provide freelysprung and substantially frictionless freedom in a direction along theaxis of the hammer while providing substantial stiffness in the othertwo mutually perpendicular directions. The flat springs mounting thehammers and the mutually perpendicular flat springs mounting the hammeractuators are conveniently stamped, cut or formed in groups of three foreasier mounting and alignment and for saving in cost. The completemodule or assembly of six hammers, six hammer actuators and sixelectro-magnets provides for three sets of the above on one side of theplane of the hammers and three sets on the other side of the same plane.The resulting assembly provides for mounting the six actuatingelectro-magnets in substantially the same plane. When a number ofmodules are stacked side-by-side, the lateral positions of theseelectro-magnets provides spacings from one magnet to its lateralneighbor which are equal to six times the pitch of the characters on thecharacter drum which provides the magnetic decoupling necessary toprevent interaction between magnets. Little or no magnetic shieldingbeing required for these magnets provides a substantial increase intheir electromagnetic efficiency.

While only one embodiment and a few modifications of the presentinvention have been shown and described, many modifications will beapparent to those skilled in the art and within the spirit and scope ofthe invention as set forth in particular in the appended claims.

What is claimed is:

1. In a high speed printer,'the combination of: a plurality of hammerseach comprising a linear bar-like element, at least two leaf springsattached to each of said elements, and mounting means for said springsoriented to resiliently hold said linear element directed toward apredetermined printing area on a high speed character drum; an actuatorfor each of said hammers comprising three arms directed outwardly fromtwo flat mutually perpendicular surfaces, two crossed flat springs oneof which is secured to each of said surfaces, mounting surfaces for eachof said springs at right angles to each other, wherein the first of saidarms is adapted to be magnetically attracted by an electromagnet, thesecond of said arms is adapted to strike one end of one of said hammersand the third of said arms is adapted to bear against an adjustable stopto control the gap between the first said arm and its attractingelectromagnet when said magnet is deenergized.

2. A combination as set forth in claim 1, wherein said crossed flatsprings are formed in groups and are interleaved along theirmidsections.

3. A combination as set forth in claim 1, wherein said arms of saidactuator are directed at angles substantially 90 degrees apart and liein one plane.

4. A combination as set forth in claim 1, and including a frame devicecarrying said mounting surfaces.

5. A combination as set forth in claim 1, and including a third leafspring for mounting each of said bar-like elements.

References Cited by the Examiner UNITED STATES PATENTS 3,012,499 12/1961Amada 10193 3,041,964 7/1962 Simpson et al 10193 3,144,821 8/1964 Drejza101-93 3,145,650 8/1964 Wright 10193 3,164,084 1/1965 Paige 101933,172,352 3/1965 Helms 101- WILLIAM B. PENN, Primary Examiner.

1. IN A HIGH SPEED PRINTER, THE COMBINATION OF: A PLURALITY OF HAMMERSEACH COMPRISING A LINEAR BAR-LIKE ELEMENT, AT LEAST TWO LEAF SPRINGSATTACHED TO EACH OF SAID ELEMENTS, AND MOUNTING MEANS FOR SAID SPRINGSORIENTED TO RESILIENTLY HOLD SAID LINEAR ELEMENT DIRECTED TOWARD APREDETERMINED PRINTING AREA ON A HIGH SPEED CHARACTER DRUM; AN ACTUATORFOR EACH OF SAID HAMMERS COMPRISING THREE ARMS DIRECTED OUTWARDLY FROMTWO FLAT MUTUALLY PERPENDICULAR SURFACES, TWO CROSSED FLAT SPRINGS ONEOF WHICH IS SECURED TO EACH OF SAID SURFACES, MOUNTING SURFACES FOR EACHOF SAID SPRINGS AT RIGHT ANGLES TO EACH OTHER, WHEREIN THE FIRST OF SAIDARMS IS ADAPTED TO BE MAGNETICALLY ATTRACTED BY AN ELECTROMAGNET, THESECOND OF SAID ARMS IS ADAPTED TO STRIKE ONE END OF ONE OF SAID HAMMERSAND THE THIRD OF SAID ARMS IS ADAPTED TO BEAR AGAINST AN ADJUSTABLE STOPTO CONTROL THE GAP BETWEEN THE FIRST SAID ARM AND ITS ATTRACTINGELECTROMAGNET WHEN SAID MAGNET IS DEENERGIZED.